In general, a SCARA robot comprises:                a base structure;        a first arm pivotally connected to the base structure about a first axis of rotation;        a second arm pivotally connected to said first arm about a second axis of rotation parallel to the first axis; and        an operating unit carried by a shaft which is mounted on the second arm and can be driven, by means of a driving assembly, in a first movement of translation along a third axis and in a second movement of rotation about said third axis, said third axis being parallel to the aforesaid first and second axes.        
In the field of industrial automation, multi-axial robots of a SCARA type are becoming extremely widespread in various production fields thanks to their relatively simple structure, their compactness, and their versatility, which renders them easily adaptable for carrying out new and different operations.
In the light of this increasingly widespread use, there is felt the need for operators in the field of industrial automation to be able to offer a range of solutions for this type of robots that is as broad as possible in order to satisfy all the specific requirements of the various applications.
In this connection, the document JP2010-158753 proposes a SCARA robot equipped with an arm that is characterized in that it has a modular structure so as to be able to assume different lengths. This solution hence enables use of one and the same robot for different applications for which the range of action of the robot changes, simply by setting the arm of the robot to the length suitable for the required range of action.